Manufacture of varnish base resin



Patented Aug.9,1938 V r 2,126,242

Maurice John Bonham, Elkins Park, Pa" 218- signor to McCloskey Vi@ompany, Holmesburg Junction, Philadelphia, v a. corporation ofPennsylvania No Drawing. Application time it, 1935,

. Serial No. 27,458 i 4 Claims. (oil. 26

This invention relates to the manufacture of varnish solvents areobtained. As the ester gum coating compositio'ns; and it comprisesmethods the glycerine esters of rosin or abietic acid are wherein tungoil is reacted with glycerine to form advantageous. It is found inpractice that the a monoglyceryl tungate, the tungate is blendedPIOPOLtiOl'l of ester gum should not be too small;

a with ester gum and the material reacted with a usually not below 120parts of ester gum to 100 u dibasic organic acid, usually phthalicanhydrid, "parts of the tungate. With variations in the the reaction.mixture being heated until resinous proportion of ester gum, resinshaving special bodies are obtained; and it further comprises'solubilities and other properties are obtained. the resins so obtainedand coating compositions In the present invention this is done:monocontaining them, together with the usual'varglyceryl tungate and anester gum being heated in nish solvents, mineral spirits, coal tarhydrotogether and an addition of phthalic anhydrid carbons, etc.; all asmore fully hereinafter set made.

forth and as claimed. All of the products are soluble in appropriate Theoily components of ,tung oil, like other varnish solvents and are usefulas and in coatvegetable and animals oils, are what are known ingcompositions for various purposes. At room id as triglycerides: eachmolecule of glycerine is temperature, they are non-tacky, solid,resinous united with 3 mols of fatty acid or is completely materials.Hard, brittle or plastic resins may be esterified. By monoglyceryltungate I mean a obtained, 'the character depending partly uponcomposition in which the ratio of glycerine to the the extent to whichresiniflcation is carried durfatty acid is three times as great; eachglycerine ing the various heating operations. Heating is moleculecarries one molecule of the fatty acid ys u c e t to Su s q y completely*of tung oil. It is really a monotungate of glycterify the acids presentso that the product has erine. a low acid number. This number is usuallyless Various fatty oils, including tung oil, may be than 12. Furtherheating increases resiniflcaheated with glycerine to produce estershaving a tion and may be used to produce resins having 25 greater ratioof glycerine to acid. Materials ap sp cial hardn ss nd' properties- Theproaching monoglycerid esters can be produced perature of h ating is abv USU/ally being and these can be resinified with the aid of ana out Thetime f heating i t e oper hydrid. The preparation of varnish resins fromtion necessarily depends to some extent 1 the certain monoglycerylesters and phthalic ansize of the batch. With a batch. of 50 gallons sohydrid has been proposed. Soluble varnish restung oil, hea i g usuallyrequires 20 m u s't ins, soluble in varnish solvents, can be preparedreach 450 F. and requires 2 hours before the in this way employingmonogly'dryl linolates. acid number is reduced to 12 or less. It is myHowever, when monoglyceryl tungate is used in belief that all thematerials enter into reaction 5 lieu of the linolate in these methods ofthe prior nd the product is mo e 01' 58 u t y in fi art, the reactionproducts are of little use being acter; it is not, apparently, a blend.insoluble, infusible resinous bodies. Further, In practici the presentve tion. the mon such methods as applied to tung oil are, however,glyceryl tungate is first formed by adding t I difllcult to control. Onething that happens durcalculated. amount of glyce ne e tune oil.

4 ing heating of the reaction mixture is livering"; and heating to about450 F. Heating is cona, phenomenon which may be described as a, tinneduntil a product soluble in an equal progelling action; possibly due topolymerization, portion of methyl alcohol is obtained. When a eitherlocal or general. The whole mass may gel test sample gives a clearsolution, in the alcohol, or there may be local formation of gelledbodies. formation of the tungate iscomplete. About 92 The gel isinfusible and is quite insoluble. With parts by weight of glycerine arerequired to con- 45 any livering, that is, production .of gelled bodies,vert439 parts of China-wood oil into the'monothe product is not usefuland even with the pro-. glycei'yl tungate, about 1 part glycerine to 4.8duction of a clear, resinous final material, it'is partschlna-wood oil.apt to be found too infusible and too insoluble in To 100 parts of thehot tungate are added at varnish solvents or thinners to be useful in a.least 120 parts of ester gum. The addition of 50 coating composition.the ester gum checks any tendency to liver and I have now found that bycombining monocools the mixture. Then the mixture is held atglyceryl'tungate with an ester gum before reabout 400 F. and stirreduntil combination is acting with the phthalic anhydrid, this liveringeffected and a clear material obtained.

is prevented and clear resins soluble in various Next, suflicientphthallc anhydrid toesterifythe 55 glycerine of the reaction mixture isadded with stirring and the temperature raised to about 450 F.'and helduntil esteriflcation is obtained and a test sample cooled to roomtemperature is a clear homogeneous resin. The heating may be stopped atthis stage or it may be continued to obtain harder resins if desired.When a test sample shows the desired consistency, solubility, etc., theheating is stopped and the molten resin is cooled to room temperature.Sometimes the resin is partially cooled and other components of acoating composition or varnish, such as solvents, etc., added beforesolidification occurs.

In the procedure set forth ante, the details may be. varied somewhat tomeet the contingencies of particular commercial embodiments thereof.Various specific embodiments illustrative of commercial practice aregiven post.

In lieu of ester gum made from rosin other ester gums, as for instancethose made from Manila copal and other resins of acid character may beused. The ester gum should have a relatively low acid number; an acidnumber of about 6. Commercially, ester gums are made in-somewhatdifferent ways and have somewhat different properties as a result, butin a general way the usual process is to mixrosin and glycerine, withplied and the excess of glycerine, if any, is distilled off. These estergums are often described as tri-esters but as a matter of fact most ofthe commercial gums appear to be mixtures of esters and containsubstantial amounts of the monoand di-esters, in addition to thetri-ester.

In the present invention, ordinarily, ester gum is first made and addedto the glyceryl tungate but in a variation of this procedure givingsomewhat different results, an excess of glycerine is used in making thetungate and then rosin, or another acid resin, such as Congo, kauri,Manila, etc or their acids, is added to the mixture which is then heateduntil it becomes homogeneous. In practicing this modification, in theinitial mixture there may be used about.25 per cent glycerine in excess.On a subsequent addition ofthe corresponding amount of rosin and heatinga good product is obtained. One advantage of this procedure is that aless amount of ester gum is required to prevent livering of theChina-wood oil. Control of the operation is easier.

Together with or in lieu of glycerine, I- may use other polyvalentalcohols, particularly those containing three or more reactive hydroxylgroups.

.Polyvalent alcohols containing but two hydroxyl groups may be used inthis way, particularly when the ester gum is formed in situ in thetungate.

Phthalic acid can be used instead of the anhydrid. Also other aromaticdibasic acids and anhydrids may be used together with or in place ofphthalic anhydrid. Polybasic aliphatic acids cient.

350 parts of ester gum for parts of tungate can sometimes be used withadvantage. With a high proportion of ester gum, however, the final resinbegins to approach the character of ester gum, it loses to that extentthe distinctive character of the resin of the. present invention. Thereis no real sharp end point as between the two types of resin. However,in all cases the resin even when it may be fairly regarded as modifiedester gum, is something of high molecular weight and complex structureand the properties are different from those of the ester gum itself. Inoperating at the stated temperatures around 450 F., the tungate radicalis to some extent polymerized; a fact which may be responsible for someof the-unique properties of resins under the present invention. In longcontinued heatingto make hard resins aftemobtaining the first orpreliminary plastic resin, rather high temperatures, up to perhaps 520F. may be used since the tungate radical has disappeared as such andthere is no longer. difliculty with livering. In the first part of theoperation temperatures around 450 F. are safer.

The following embodiments in which the parts are parts by weight,further illustrate the presen invention:

Example 1.-Into a suitable vessel usually a closed container: equippedwith heating and agitating means, there are introduced 439 parts ofChina-wood oil and 92 parts of glycerine. The materials are heated toabout approximately 450 F. and stirred at that temperature until a testsample dissolved inan equal weight of methyl alcohol-yields a clearsolution. Usually about 6 to 8 hours heating at said temperature issuiii- At room temperature this monoglycerid product is a highly viscousliquid of cloudy appearance, soluble 50 per cent by volume in C. P.methyl alcohol.

Example 2.In making an ester gum particularly suitable for use in thepresent invention, 100 parts of rosin are heated to approximately 525 F.temperatures until 'a clear molten mass -is obtained. To this isgradually added 10 parts of glycerine, the mass being stirred duringthis addition. The stirring is continued and the mixture.

held at 525 until the rosin is esterifled and an ester gum having anacid number of about 6 is obtained upon cooling.

Example 3.--To 100 parts of the monoglyceryl tungate obtained in Example1 are added parts of the solid ester gum. This checks any liv-.

ering of the tungate and cools it. This mixture is brought to and heldat approximately 400 F. until a clear hot material is obtained. To thishot liquid is added 40 parts of phthalic anhydrid with stirring. and thetemperature is brought to and maintained at about 450 F. yHeating for 15minutes is often suflicient. When a sample dropped on a glass plateremains clear and has an acid'number of 8 to 10 the mass is cooled,

" enough to permit admixture of the desired solvent, toluol or benzolfor example. The resinous material is soluble in coal tar oils, inesters and in ketones. It is,not, however, soluble inpetroleumhydrocarbons. A varnish made with an equal weight of toluol has aviscosity of 2.00 poises and may be used for the usual varnishingpurposes.

In the particular described operation the ratio of ester gum is ratherlow and it is desirable that heating be interrupted by cooling andintroducing the solvent when test shows production of a clear resin. Butas stated, heating should be long enough to give a low acid number andcomplete union or combination of all the reactants.

In the operation of this example, and in all other embodiments of thisinvention, completeness of reaction is essential in obtaining a varnishbase which behaves as a unitary material; is uniformly soluble invarnish solvents. Materials which have not undergone reaction may becomesegregated in cooling or in solution in the varnish solvent. Both areundesirable. By using the conditions described, there is no formation ofinsoluble side reaction products which may cause trouble. In all cases,when a test sample cooled to room temperature remains clear and isuniformly soluble in a solvent,- the reactionhas gone forwardlyproperly.

In the operation of Example 3 omitting ester gum or reducing theproportions, results in insoluble products when the phthalic anhydrid isplaced in reaction.

In commercial practice I have found that it is safer and better to use aproportion of ester gum somewhat above the amount required to justprevent livering.

Example 4.-In another procedure. the operation is substantially the samebut the proportions used are 100 parts monoglyceryl tungate 40 partsphthalic anhydrid 1'75 parts ester gum About 1 hour is required to givea clear cooled test sample with an acid number of 10 to 12. The moltenresin is cooled and reduced with varnish solvents as before.

In this particular operation the mix appears about to liver after 40minutes at 450 F.. but

heating may be continued tor two hours without livering occurring. Thislonger heating does not cause any great change in'the' resin.

The resins obtained are soluble in coal tar hydrocarbons, esters and-ketones. They are insoluble in petroleum hydrocarbon used alone, butare soluble in a mixture of petroleum hydrocarbon and coal tarhydrocarbons in the ratio of :15 of the former to the latter. words. asolution obtained by cutting a artially cooled resin with benzene ortoluol tolerates large additions of petroleum oils, such as turpentinesubstitutes. i

In this particular case. and in most other cases. in cutting thepartially cooled res n it is desirable to use mixed solvents containingpetroleum hydrocarbons, gasoline. turpentine su stitutes, naphtha. etc.Sometimes solvent may be added in stages: first benzol or toluol andthen a thin petroleum oil.

The resins obtained in Example 4 are soluble in and miscible withblownlinseed oil to make valuable coating compositions. The resins may beadded to the oil and the mixture heated unt l solution occurs. tageouslyabout 350 F. in making a blend. Blown linseed oil may be added to thevarnishes obtained by thinning the resins. Dried films obtained fromcompositions containing blown linseed oil are clear and dry; showing nocloudiness or precipitation.

The resins made as so far describedare, however, not directly soluble inordinary-'unoxidized drying oils such as linseed oil, China-wood oil andthe various other commercial drying oils. They are not soluble in standoil; preparations In other dry tack free in about 3 to 4 hours.

The temperatures are advan-' obtained by polymerizing linseed oil at atemperature around 600 F.

Example 5.In another embodiment of this invention, the procedure is thesame as in Example 3 except that the proportions are The resins obtainedare soluble in petroleum hydrocarbon as well as in the other solventsmentioned. They are, however, somewhat harder and more brittle; theygive a harder varnish. Heating in this example may be continued up to 2hours with a progressive increase in hardness.

Ercample 6.--In another embodiment of the present invention theconditions set forth in Example 3 are somewhat modified. To 439. partsof China-wood oil are' added 116 parts of glycerine; an amount 25 percent in excess of that necessary to produce the monog'lycerid. As beforethe reaction mix is brought to and maintained at about 450 F. until amonoglycerid results. Tothe hot mixjd5jparts of rosin are added perparts of reaction mixture. This cools it somewhat. Heating is continuedat 400 F. until all the material has gone into reaction and a clear testsample can be obtained. At this time 40 parts phthalic. anhydrid areadded and the mixture heated at 450 F. as in Example 3.

In Example 1 ester gum was formed separately and added While in Example6 reaction between rosin and glyoerine occurs in the reaction mixture.

Example 7.--Using a reaction mix containing 100 parts monoglyceryltungate 40 parts phthalic anhydrid 290 parts ester gum and made ineither way after addition of phthalic these resins withChina-wood oil.The resins are not, however. easily soluble in linseed oil.

Admixture with tung oil may be made prior to complete cooling of theresin.

Example 8.--In making such a blended product to 100 parts of the moltenresin of Example 7 are added'156 parts of tung oil (20 gallons) and themixture held at approximately 525 F. until test sample, on cooling,gives a clear, uniform, plastic varnish base. This may be reduced with250 parts by weight of turpentine or mineral spirits- The varnish soobtained has a viscosity of 2.00 to 2.50 poises and gives coatings whichair- The airdried coating may be baked at 250 F. for further hardening.Driers are added to this varnish and the others described. Addition maybe to the molten resin or to the reduced solution.

By varying the proportion of tung oil within a range of say 40 to 400parts by weight, varnishes of diflerent properties may be obtained;these being shorter orlonger in oil. This wide range of miscibility isadvantageous. Prior varnish resins mostly have a more restricted rangeof m scibility.

Example 9.-The directions in Example 7 may be varied by slightlyincreasing the amount of ester gum, using 300 to 100 parts ofmonoglyceryl tungate in lieu of 290. In so doing, complete miscibilitywith linseed oil is obtained. The products are soluble in all the othersolvents previously mentioned including tung oil.

Example 10;In making a linseed oil blend, to 100 parts of the varnishbase obtained according to Example 9, 80 parts or preheated linseed oilare added and the mixture held at 550 F. until a test sample gives anon-taclw, clear, uniform base. About 2 hours heating are required. Thisvarnish base reduced with solvents gives a good short oil varnish.Thinning may be by an equal amount of toluol or mineral spirits.

The relative amount of linseed oil may be increased to produce varnisheslonger in oil. As much as 250 parts of oil to 100 parts of resin may beused and varnishes rapidly drying to a tack-free coating obtained. Withvarnish bases long in oil a longer cooking is advantageous.

A characteristic of the oil soluble resin obtained under the presentinvention is that their miscibility is better in tung oil than inlinseed oil. With most prior varnish bases containing a synthetic resinthe reverse is true. Some of the varnish resins oi the prior art gaveonly short oil varnish, whereas othersonly gave varnish long in oil.Here either type oi oil varnish may be obtained at will, without thenecessity of using special blends oi. drying oils or particular mixtureof varnish solvents to obtainclear good varnishes.

The varnish bases produced in the present invention are, as stated,unitary in their nature; they do not segregate anything on mixing withsolvents, linseed oil, etc.; they give single-phase homogeneoussolutions. Preparations made by a simple mixing together of ester gumand any of the resins based on phthalic anhydrid, even where blending isaccompanied with a little heating, are not unitary; the two componentsretaining their individual solubilities. --It. is practically impossibleto make. good varnish with a mixture giving any segregation in themanufacture of varnish base or in cutting the base to make a varnish.Ester gum has an excellent range of solubilities, but it is not as hardas can be desired. the present invention, in one way of looking at it,without forfeiting the good range of .solubilities of ester gum'; it isgiven a harder character; it

. is made better adapted for giving a good varnish of the hardnessconmiercially desired. For another thing, it is found that thecompounded materials under the present invention are considerably moreresistant to water than are most of the resins based on phthalicanhydrid. The water resistance of varnishes made under the presentinvention is good; they are well adapted for outside use, onautomobiles, houses, etc. The varnishbases are particularly adapted foruse in making baking oil varnishes.

What I claim is:

1. In the manufacture of resinous condensation products useful asvarnish bases, from monoglyceryl tungate and phthalic acid by "reactingsaid tungate with said acid, the improvement which comprises blending anester gum with said tungate prior to reacting with phthalic acid, thesaid! blending being elected by heating the said ester gum and saidtungate until a clear solution is obtained and the said ester gum beingso blend withsaid. tungate in a ratio of at least 120 its by weight ofester gum to 100 parts of the tungate, the amount of ester gum beingsunlcient, upon subsequent reaction of the mixture with phthalic acid toproduce a clear homogeneous soluble resin.

2. In the manufacture of varnish bases from monoglyceryl tungate andphthalic acid, said varnish bases being soluble in coal tarhydrocarbons, in petroleum hydrocarbons and in tung oil, the processwhich comprises adding approximately 290 parts of ester gum to 100 partsof monoglyceryl tungate, heating the mixture to approximately 400 1''.until a clear solution is obtained,

adding to the hot liquid 40 parts of Dhthalic anhydrid and furtherheating the mixture to approximately 450 1''. and maintaining themixture at that temperature until a clear hard resin is obtained uponcooling, said resin having an acid number of less than 12 and beingsoluble in tung oil, in petroleum hydrocarbons and in coal tarhydrocarbons.

3. As a new varnish base, the clear hard resin ous product obtained bythe process of claim 2, said hard resin beinga homogeneous unitary resincontaining said tungate chemically combined with phthalic anhydrid,having an acid number less than 12 and being soluble in petroleumhydrocarbons, coal tar hydrocarbons and tung oil, but being insoluble inlinseed oil.

4. The process or making a varnish base resin capable of going intohomogeneous solution with linseed oil and tung oil, said base beingsoluble in coal tar hydrocarbons to give solutions tolerating admixturewith petroleum. hydrocarbons which comprises heating tung oil with asumcient amount of glycerine to give a monoglyceryl tungate completelysoluble in methyl. alcohol, heating the monoglyceryl tungate with atleast 120 per cent of ester gum ,at about 400 F. until a clear solutionresults, adding to the hot liquid phthalic anhydrid an amount aboutequal to 40 per cent 01' the monoglyceryl tungate and heating themixture at about 450 F. until a clear hard resin is obtained on cooling,said resin having an acid number less than 12.

